Its controlled by selecting "auto" on the steering column stalk.
Though you can have daylight running lights selected on the computer so the headlights stay on all the time the engine is running regardless of daylight levels.

I know you need to select auto in the Steering column and it is selected but it works only in the night. During the day the lights can be turned on only manually . this is why I started thinking it could be a wrong setting. The manual is not clear on that.

The computer was reset because it kept giving an alarm of the turbo malfunctioning. After only 6,000 Km the turbo was changed and after further investigation the garage got to the point that it was a computer issue and they reset it......... they should have done before changing the Turbo..

If your referring to your headlights, those will only ever come on when set to manual or as the evening approaches when set to automatic. The lower lights, that also serve as fog lights if installed, are your day running lights. Those lights will be on constantly with the right setting.